DE 101 23 190 A1 discloses a fuel filter with means for separating water. The filter is of a two-stage configuration with two cylindrical filter elements inserted into each other through which, in radial direction, fuel is flowing wherein the upstream filter element is comprised of hydrophilic material and downstream filter element is comprised of hydrophobic material. After flowing through the first hydrophilic filter, the purified fuel, including water proportions, reaches the outer mantle surface of the second hydrophobic filter where the water is separated and is guided in axial direction downward.
WO 2008/077954 A2 discloses a fuel filter that comprises an annular filter element to be flowed through in radial direction from the exterior to the interior as well as a mesh element that is also annular and is received in the filter element. The fuel is first passed through the filter element in radial direction for particle filtration and, before flowing into the mesh element, must first flow across the bottom edge of a housing insert which serves for diverting the fuel. In the area of the lower end face edge of the housing insert, a first water separation takes place, followed by a second water separation on the mesh element.
The invention has the object to provide a filter device with improved efficiency with respect to separating particles or entrained medium.